Biodegradable copolymer, a biodegradable polymer composition, a biodegradable article, and a preparation process thereof

Abstract

Disclosed are a biodegradable copolymer and a biodegradable article molded therefrom, said copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 consisting essentially of (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural units and (B) from 95 to 1% by mol of oxetane structural units, said structural units being combined in the state of a block, and containing an organic aluminum-based Lewis acid represented by general formula (I) ##STR1## wherein R is an alkyl group having a carbon number ranging from 1 to 4, Y is independently selected from a substituted group, and p is any one of 1, 2 and 3. Also disclosed are block polymers of lactone and dimethyltrimethylene carbonate and blends of polylactone with polyoxetane.

What is claimed is: 
     
       1. A biodegradable copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 consisting essentially of (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural units and (B) from 95 to 1% by mol of oxetane structural units, said structural units being combined in the state of a block, and containing an organic aluminum-based Lewis acid represented by general formula (I) ##STR7## wherein R is an alkyl group having a carbon number ranging from 1 to 4, Y is independently selected from a substituted group, and p is any one of 1, 2 and 3. 
     
     
       2. A biodegradable copolymer as set forth in claim 1, wherein said average number molecular weight ranges from 30,000 to 300,000. 
     
     
       3. A biodegradable article molded from a copolymer having a number average molecular weight ranging from 1,000 to 1,000,000 consisting essentially of (A) from 5 to 99% by mol of epsilon-caprolactone or delta-valerolactone structural units and (B) from 95 to 1% by mol of oxetane structural units, said structural units being combined in the state of a block, and containing an organic aluminum-based Lewis acid represented by general formula (I) ##STR8## wherein R is an alkyl group having a carbon number ranging from 1 to 4, Y is independently selected from a substituted group, and p is any one of 1, 2 and 3.